ENTOMOLOGY. 461 



the mean temperature falls below 55° the parasites do not multiply rapidly 

 because it requires nearly a month or even more for them to develop. During 

 the hot months of July and August they decrease in numbers because of a lack 

 of hosts, since the green bugs can not endure temperatures much above 100°. 



A synopsis of the genus Pemphigus with notes on their economic impor- 

 tance, life history, and geographical distribution, C. F. Jackson {Jour. Colum- 

 bus Hort. Soc, 21 (1907), pp. 160-218, figs. 3).— Twenty-three species of Pem- 

 phigus are described as occurring in America. 



Plant bugs injurious to cotton bolls, A. W. Morrill {U. 8. Dept. Agr., Bur. 

 Ent. Bui. S6, pp. 110, pis. .5, figs. 2o). — The first part of this bulletin is devoted 

 to a general consideration of the nature and amount of damage that the true 

 bugs do to cotton and the part they take in tlie dissemination of plant diseases. 

 Because of the fact that when dry the damaged boll gives by itself no direct 

 evidence of the cause of its condition, the importance of plant bugs as cotton 

 pests has been almost completely ignored. Although no spotting of the bolls is 

 known to result directly from the attacks of the representatives of the heterop- 

 terous families thus far studied, the bolls, even when as large as IJ in. in diam- 

 eter, may, when severely attacked by plant bugs, flare, turn yellowish, become 

 flaccid, and finally fall to the ground. The most essential factor in determining 

 injui'y to the bolls is the appearance of the inner side of the carpels, wliere the 

 point of entrance of the insect's setae is marked by a minute dark spot sur- 

 rounded by a watery, or blisterlike, bright green area, contrasting distinctly 

 with the light, dull-greenish background. An examination of 100 injured bolls, 

 revealing over 4,000 punctures by plant bugs (practically all by Pentatoma 

 Ugata), developed the fact that 34 per cent of the punctures had resulted in 

 proliferation. In general, bolls damaged by plant bugs when open are char- 

 acterized by more or less shriveled locks and only partial spreading of the 

 carpels. In addition to destroying the bolls, many of the plant bugs cause more 

 or less staining of the fiber and thus reduce the quality. 



Investigations of the conchuela {Pentatoma ligata) of which preliminary 

 accounts by the author have been previously noted (E. S. R., 17, p. 782; 18, 

 p. 952) are reported upon at length. Detailed accounts of its life history and 

 habits, technical descriptions of its several stages, destructiveness, natural and 

 ai'tificial control, etc., are given. In Mexico the grain bug {P. sayi) has been 

 observed to be of frequent occurrence on cotton and to resemble the conchuela 

 in habits, life history, and seasonal history. It is thought tliat the preference 

 of this species for the seed of grains and alfalfa will be sufficient protection 

 against its occurring in injurious abundance in cotton fields in this country. 

 The brown cotton bug {Euschistus servus) which occurs throughout the South- 

 ern States has been observed in limited areas comprising only a few acres each 

 in numbers whicli caused destruction of the majority of the cotton bolls. As 

 many as 162 eggs were observed to be deposited by a single specimen. "At an 

 average daily mean temperature of 78.9° F., the average incubation period of 5 

 batches of eggs was found to be 4 days and 17 hours. The <lnration of the 

 nymphal stages corresponds closely with tliat of the conchuela." Telcnomus 

 ashmeadi parasitizes its eggs. The green soldier bug {Nezara Jiilaris) is the 

 most common pentatomid found on cotton throughout the Southern States. 

 Although a very general feeder, it shows a preference for cotton bolls. 2V^. 

 viridula which occurs throughout the cotton belt injures cotton bolls as well as 

 potatoes, sweet potatoes, oranges, etc. Thyanta custator is one of the most 

 common pentatomid bugs in Texas. In selecting food plants, it has tlius far 

 exhibited a preference for grains and cotton. In the laboratory T. axhmeadi 

 has beeu reared from the eggs of this species and egg-batches have been cdllccted 

 in the field from which parasites had emerged. Other i)entatomids meutioiied 



